In recent years, content playback systems that distribute contents, such as moving pictures, telops, and still images, that display these contents on multi-screens, and that provide information to users on an multi-facet basis have come into wide-spread use.
In these content playback systems, multiple contents that are displayed on a multi-screen basis are displayed in synchronization. For example, Patent Reference 1 describes an apparatus comprising data request receive means and a control data generation unit. The data request receive means send requests on media data on first and second foreground images to a server and receive messages from the server. The control data generation unit controls said data request receive means so that, based on the information that indicates the wait time before the start of display of each foreground image contained in SIML (Synchronized Multimedia Integration Language) data, said data request receive means issue a message requesting media data to the corresponding server at a time earlier than the starting time for the display of each foreground image by said wait time. By this constitution, this apparatus makes it possible to display the first and second foreground images by combining them with a background image at a time specified in the scene description in the SMIL data.
Further, Patent Reference 2 describes an apparatus capable of playing back content data, such as multimedia scenes while satisfying the time specification by scene description information, reducing the time delay until the start of playback or until the start of the next playback, and also reducing the buffer area. This apparatus, while entering, by means of a transceiver, scene description information that specifies temporal sequence related to the playback of contents, measures the vacant band width on the network. In addition, it provides scene description information to a transfer scheduling unit and if a vacant band width exists, it requests from the content distribution apparatus the moved up transfer of contents data, time-wise lagging the previously received content data, based upon scene description information.